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HUBBARD AND CRONEIS 
and includes many shale and sandy lenses and partings. It is for 
the most part rather heavy bedded and dense, but includes such 
wide variations in its great thickness that it is hard to gen- 
eralize. It carries a large amount of chert in lenses and in 
nodules, the chert being both light and black, but the light is in 
great preponderance and the black occurs only in the lower 
layers. 
The formation is for the most part calcite veined, with calcite 
nodules and calcite-filled cavities numerous. Pyrite occurs in the 
shape of pyritohedrons, and limonite and hematite pseudomorphs 
after these crystals are not uncommon. Fossils are uncommon in 
the limestone but a few gastropods occur as well as other fossils 
too fragmentary to be recognized. However, in some places the 
chert is quite fossiliferous and gastropods, brachiopods, and 
sponges can be identified. 
The rock usually weathers light and has an uneven to conchoi- 
dal fracture. Many layers are wave marked. The jointing is as a 
rule not pronounced; however, it is so good in the county road 
cut along Walker Creek between Bane and Staffordsville, that the 
joint planes are with difficulty distinguished from the bedding 
planes. Practically all the valley floors are made up of Shenan- 
doah Limestone, and the white chert remaining after the lime- 
stone has disintegrated is found widely scattered. 
The limestone is quarried in several places in this region and 
is used extensively for ballasting, for lime making and for build- 
ing purposes. The soil resulting from its disintegration is rich 
and productive. 
The Shenandoah Subdivided 
Section along the Virginian Railroad cut at 
the Narrows of the New River 
1. Gray blue, fine grained, rather massive limestone, with 
shale partings of one to three inches. Flattened layers of black 
chert and a few small calcite veins. The limestone layers are 
from several inches to three feet in thickness. The formation 
weathers light buff to white, losing all the blue. The fracture is 
uneven to conchoidal with minor jointing vertical to the bedding 
planes. No fossils seen. Dolomitic. 25 feet. 
2. A gray blue, fine grained, massive limestone with no chert, 
having, however, nodules and veins of calcite arranged in all 
